The present invention relates to color imaging devices and more particularly to such a device fabricated from a two dimensional horizontal array of vertically stacked photovoltaic devices.
Considerably progress has been made in development of practical thin film photovoltaic devices. U.S. Pat. No. 4,388,482 issued to Hamakawa et al on June 14, 1983 teaches the construction of a p-i-n amorphous silicon photovoltaic cell and is hereby incorporated by reference for such teachings. While that patent is primarily involved with providing a solar cell with improved efficiency, that is greater power output, it also teaches that electrical bandgap, and therefore color band absorption and electrical response, of the resulting cell can be adjusted by appropriate selection of materials.
U.S. Pat. No. 4,292,092 issued to Hanak on Sept. 29, 1981 provides several additional teachings relating to assembly of photovoltaic cells into practical modules. The primary teaching involves the use of laser processing to scribe various conductor layers so that a monolithically fabricated panel may be cut into a number of series connected individual cells which improves efficiency by reducing resistive losses. In addition Hanak teaches the use of tandem, or stacked, series connected solar cells in such a module arrangement. The Hanak patent is also incorporated by reference.
Amorphous silicon structures have been used as active devices in an otherwise conventional vidicon type image pickup tube. See for example the publication, "Single-Tube Color Imager Using Hydrogenated Amorphous Silicon", by Sachio Ishioka, et al, Proceedings of the 14th Conference (1982 International) on Solid State Devices, Tokyo, 1982; Japanese Journal of Applied Physics, Volume 22 (1983) Supplement 22-1, pp. 461-464. Color separation is obtained by use of striped shaped organic filters so that color signals from each picture element are obtained from slightly different parts of the actual image.